Montana Department of Transportation

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Fuel Taxes


Each year the Montana Department of Transportation (MDT) is required to determine fuel tax allocations distributed to Montana's cities, counties, and consolidated city-county governments set forth in 15-70-101 MCA, as amended.

One of the factors used to calculate the amount allocated to each local entity is road mileage. Mileages for counties consist of any road exclusive of the National Highway and Primary Systems within the county boundary and outside any incorporated city limits that meet the criteria of "open to public travel" as stated below:

Open to Public Travel is defined as a segment of road available for public use except during periods of extreme weather or emergency conditions, passable by a 2-wheel drive passenger car and open to the general public. Restrictions include; primitive trails, driveway to a single residence, field access roads, parking lots, restrictive gates, orange markings on posts, or "No Trespassing" signs (MCA 45-6-201).

MDT conducts field inventories yearly to collect new road coordinates using GPS technology and to ensure the roads are "open to public travel".

Our database is continuously updated. In addition to the annual mileage certification returns from the cities and counties, results from field reviews and the discovery of errors can have an effect on the mileage numbers from year to year.

Fuel Tax Maps

These maps show roads that are designated "Open to Public Travel", as defined above, along with rejected roads that do not meet our requirements identified by MDT field inventory. The data provided in these maps is to only be used by Montana city and county governments for reference during MDT's fuel tax allocation process. Official fuel tax roads and mileages are held in the office of MDT. For requests or comments please contact Brian Andersen at or 406-444-6103.

Interactive Fuel Tax Map
Montana's Current Fuel Tax Routes
Fuel Tax Maps sent out during our SFY2017 City/County Certification process
County | City

ArcGIS Server Connection

To add this service in ArcGIS you can either:

  1. Download an ArcGIS Layer "MDT_FT_Routes" and add it to ArcMap.
  2. If you would like to add this as an ArcGIS Server connection
    1. Connect in ArcCatalog using this Internet Server URL: ""
    2. When connected go to Custom then MDT_FUEL_TAX feature service.

Submitting GIS Data

To submit changes in an electronic GIS format, please contact Brian Andersen at or 406-444-6103 for assistance.

Disclaimer: All data and maps are provided "as-is" without warranty of any kind. The Montana Department of Transportation makes no representations or warranties whatsoever with the respect to the accuracy or completeness of these data sets and assumes no responsibility for the suitability of these data sets for a particular purpose; and MDT will not be liable for any damages incurred as a result of errors in these data sets.